It was the fourth straight game that Dempsey has scored against the Timbers. It was his sixth over goal against them, the most by anyone since the series moved to Major League Soccer.

“It’s always good to score against your rivals,” Dempsey said. “I try to score every game. Anytime you can score goals, they always feel good, but it’s a little more special when you can score one against your rivals, and especially a game winner.”

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The Sounders said they were surprised by how conservatively the Timbers opened the game. Still, Seattle had several good chances in the first half, but none found the net.

The breakthrough came in the 77th minute, when midfielder Andy Rose put a shot on goal. Portland goalkeeper Adam Kwarasey blocked it but couldn’t control the ball, and Dempsey swooped in and touched it across the line.

“I was surprised that the ball was still fumbling around, but I was happy that it was,” Dempsey said. “I was able to sneak in and get a goal.”

The result moved the Sounders to 4-2-1 on the season and 1-0 in the Cascadia Cup competition. Portland fell to 2-3-3 in MLS play and 0-2 in the Cup.

The crowd of 41,451 moved the Sounders into the league lead with an average home attendance of 40,067,

Next, the Sounders head out for three straight road games. They will start Sunday with their first visit to Yankee Stadium and New York City FC before continuing on to Columbus and Vancouver. Their next home match is May 23 against Sporting Kansas City.

Final: Sounders 1, Portland 0. Seattle moves to 4-2-1 in MLS and 1-0-0 in Cascadia Cup. Timbers fall to 2-3-3 in MLS and 0-2 in Cup.

77' GOAL Sounders. Rose, who just checked in puts it on goal, saved, but Dempsey touches trickling ball across line. Seattle, 1-0. That's Dempsey's sixth in the Sounders-Timbers series, most of any player in the MLS series. Also his fourth straight game scoring against Portland. Also ties him with Oba for 2015 team lead with four goals.

75' Portland goals leader (three) Fanendo Adi check in for Urruti.

Attendance: 41,451. Sounders' season home attendance average climbs to 40,067, tops in MLS. Orlando City slipped to second at 39,328.